feat: Add technical documentation for SpotterCopilot

[Grandpied33]

This commit introduces a comprehensive technical documentation file (DOCUMENTATION.md) that details the project's architecture, backend and frontend components, data flow, and configuration.

It also updates the .gitignore file to properly exclude Python cache files.

[Copilot]

Pull Request Overview

This PR adds comprehensive technical documentation for the SpotterCopilot project. The documentation provides detailed insights into the project's architecture, components, and data flow, making it easier for developers to understand and contribute to the codebase.

• Introduces a new technical documentation file (DOCUMENTATION.md) written in French
• Documents the RAG (Retrieval-Augmented Generation) architecture and Azure service integrations
• Explains backend processing flow, frontend structure, and configuration requirements

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_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Corrected spelling of 'ressources' to 'resources'.

Suggested change

	- **`ressources/Large_Exercises_CSV.csv`** : La source de connaissance principale de l'agent. Ce fichier CSV contient une liste d'exercices avec des descriptions, des groupes musculaires ciblés, etc. Il est importé dans Azure AI Foundry (ou Azure AI Studio) pour créer l'index de recherche.
	- **`resources/Large_Exercises_CSV.csv`** : La source de connaissance principale de l'agent. Ce fichier CSV contient une liste d'exercices avec des descriptions, des groupes musculaires ciblés, etc. Il est importé dans Azure AI Foundry (ou Azure AI Studio) pour créer l'index de recherche.

[Grandpied33]

@copilot What's wrong ?
---End of Oryx build logs---
Function Runtime Information. OS: linux, Functions Runtime: ~4, python version: 3.11
Finished building function app with Oryx
Zipping Api Artifacts
Done Zipping Api Artifacts
The content server has rejected the request with: BadRequest
Reason: The size of the function content was too large. The limit for this Static Web App is 104857600 bytes.

For further information, please visit the Azure Static Web Apps documentation at https://docs.microsoft.com/en-us/azure/static-web-apps/
If you believe this behavior is unexpected, please raise a GitHub issue at https://github.com/azure/static-web-apps/issues/
Exiting